P-GLYCOPROTEIN EXPRESSION AS UNFAVORABLE PROGNOSTIC FACTOR IN ACUTE MYELOID-LEUKEMIA

In order to further define the role of the MDR1 gene in acute myeloid leukemia (AML), we determined the association between the presence of P-glycoprotein on leukemic cells and the efficacy of therapy in patien ts with AML. Immunocytochemistry with monoclonal antibody C219 was per formed to demonstrate the presence of P-glycoprotein. Positive stainin g ranged from 0 to 60% of the leukemic cells. For further analysis, pa tients were assigned into groups with 0-5% staining cells (group 1, n= 33) and with >5% staining cells (group 2, n=19). The complete remissio n rate of induction chemotherapy was 76% for group 1 but only 32% for group 2 (p=0.002). The median duration of overall survival was 19 mont hs for patients in group 1 as compared to 3 months for patients in gro up 2 (p=0.007). The data indicate that P-glycoprotein expression is as sociated with an unfavorable prognosis in patients with AML.